Walk behind mower

ABSTRACT

A walk behind mower includes an engine-driven transmission for driving a pair of wheels at rate that varies according to the position of a transmission setting control selected by an operator. The transmission setting control positions a member that has a stop surface proximate to a transmission speed input on the transmission. The transmission speed input is adjusted by one or more levers on a handle of the mower. The transmission setting control is adjusted to define a home position of the stop surface relative to the transmission speed input and define a range of travel of the transmission speed input before it contacts the stop surface. The member is spring biased toward the home position but is moveable away from the home position. The position of the transmission speed input when it contacts the stop surface defines a first rate of travel of the transmission. An operator applies a first amount of force to the lever until the transmission speed input contacts the stop surface. The operator can apply a second greater amount of force to the lever that exceeds the spring biasing force on the member to further move the transmission speed input to define a second higher rate of travel of the transmission.

CROSS-REFERENCE TO RELATED APPLICATION(S)

Priority is claimed under U.S. Provisional Application No. 60/488,533,entitled Walk Behind Mower, and filed Jul. 18, 2003, which isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates to mowers with mechanisms for adjustingdrive speed. In particular, the present invention relates to mowers withan independent transmission for each of two rear drive wheels.

Adjustment of the deck height determines the amount of vegetation thatis cut. For example, at golf courses, the fairways are mowed at a muchshorter deck height than are the rough or out of bounds. It is alsoadvantageous to be able to adjust the deck height setting on mowers usedby homeowners as grass height preferences tend to vary between ownersand additionally it is often necessary to adjust the deck heightdepending on the terrain that is to be mowed. Sloped and uneven groundoften requires the use of a higher deck height than level ground.Adjustments of the deck height for walk behind mowers is time consuming.The adjustment requires the engine of the mower to be shut off and, insome cases, manual adjustments of each corner of the deck must be made.

With respect to the rate of travel of the mower, the speed is a functionof a transmission control that varies the rate at which the drive wheelsare driven by the transmission. Hydrostatic transmissions, for example,are one type of transmission known in the art and include fluid pumpsdriven by the mower engine, and a hydraulic motor for transforming thehydraulic power into torque and rotation speed for operating the wheels.Once the transmission control is adjusted to a desired rate of travel,the operator activates one or more levers on the mower to engage thetransmissions. The operator then operates the mower at the operatingspeed selected. At the end of a cutting pass, the mower is steered to anew cutting direction by operating only one of the hydrostatic drives ofthe rear wheels. If the mower is to be driven at a higher rate of speed,such as is desirable when moving the mower from one area to a moredistant area, the mower is stopped by releasing both transmissionengagement levers, readjusting the transmission rate control, and thenreengaging the transmission engagement levers.

As time and efficiency are important factors in mowing, improvements indeck height adjustment and drive speed adjustment are needed in mowers.

BRIEF SUMMARY OF THE INVENTION

In one embodiment, the present invention is a walk behind power mowerthat can be operated at a first speed determined by the operator and asecond speed greater than the first speed without having to adjust atransmission speed setting of the mower. The mower includes an operatorhandle and a lever on the operator handle that moves between a startingposition and a second position.

The lever is operably connected to a transmission speed input whichrotates to vary the rate of speed of the transmission. The transmissionis in neutral when the lever is in the starting position and thetransmission is at a highest rate of speed when the lever is in thesecond position.

A first member is connected to the transmission speed input and rotatestherewith. A second member has a stop surface that engages the firstmember when the first member contacts the stop surface. The secondmember is biased toward a home position near the first member and ismoveable away from the home position.

In operation, an operator applies a first amount of force to the leverto move the lever away from the starting position. In response, thefirst member rotates and engages the stop surface before the lever canmove to the second position, thereby defining a first rate of speed ofthe transmission. The operator applies a second amount of force to thelever to move it toward the second position. The further movement of thelever causes further rotation of the first member and movement of thesecond member away from the home position to permit a second higher rateof speed of the transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of the mower of the presentinvention.

FIG. 2 is an enlarged partial perspective view of the lift mechanism forthe mower of the present invention.

FIG. 2A is a perspective view of the lift mechanism for the mower of thepresent invention with the mower deck removed.

FIG. 3 is a sectional view taken along line A—A in FIG. 1.

FIG. 4 is an enlarged view of the deck height setting mechanism of thepresent invention.

FIG. 5 is a rear view taken of the deck height setting cam of thepresent invention.

FIG. 5A is an enlarged view of the deck height setting cam of thepresent invention.

FIG. 6 is an enlarged view of the deck height setting mechanism of thepresent invention.

FIG. 7 is a rear view of the mower of the present invention.

FIG. 8 is an enlarged rear view of mower 10 of the present invention.

FIG. 9 is an enlarged rear view of mower 10 of the present invention.

FIG. 10 is an enlarged rear view of mower 10 of the present invention.

FIG. 10A is an enlarged rear view an alternative embodiment of mower 10of the present invention.

FIG. 11 is an enlarged view of the handle of the present invention.

DETAILED DESCRIPTION

FIG. 1 is a perspective view of one embodiment of a mower of the presentinvention, generally referred to as mower 10. Mower 10 is a walk-behindlawn mower that provides both a rapid and efficient system for adjustingthe height of deck 24 and an advantageous drive system. As illustratedin FIG. 1, mower 10 generally includes frame 12, engine 14, front wheels16, left rear wheel 18, right rear wheel 20, handle 22, deck 24, liftingmechanism 26, and foot pedal 28. The designated left and rightidentifiers refer to components generally viewed from the perspective ofan operator operating mower 10.

Frame 12 carries engine 14, which provides power for various moweroperations, and handle 22, which supports various controls for mower 10,including a deck height setting control 30. Herein, the term “mowerbody” generally refers to frame 12 along mower 10, as illustrated inFIG. 1. Deck 24 is supported beneath frame 12 and houses one or morecutting blades that are driven by engine 14. Frame 12 is supported byfront wheels 16, left rear wheel 18, and right rear wheel 20. Left rearwheel 18 and right rear wheel 20 are each driven by its own hydrostatictransmission in a manner known in the art. Deck 24 is further associatedwith lifting mechanism 26, which raises and lowers deck 24. Liftingmechanism 26 is linked to foot pedal 28, which is located at the rear ofmower 10.

When an operator desires to adjust the height of deck 24, the operatordepresses foot pedal 28, which operates lifting mechanism 26 to raisedeck 24. The operator then sets the desired height of deck 24 via deckheight setting control 30. The operator then releases foot pedal 28,which allows lifting mechanism 26 to lower deck 24 down until deck 24reaches the selected height. As such, mower 10 reduces the time andeffort required to adjust the height of deck 24, as compared to standardcommercial mowers, and provides a safe way to adjust the height of deck24 without having to shut down engine 14. This allows the operator tomow areas with uneven ground or that require different length cuts muchquicker, which saves time, energy, and money.

FIG. 2 is an enlarged partial perspective view of mower 10 illustratingthe lifting mechanism 26 for the deck 24. FIG. 2A is a perspective viewof the lifting mechanism 26 with the deck 24 removed, in which thelifting mechanism 26 connected to a deck height adjustment apparatus 29.As shown in FIGS. 2 and 2A, the lifting mechanism 26 is comprised of afront lift assembly 25 and a rear lift assembly 27 that is supportedbetween a left frame member 12 a and a right frame member 12 b. The rearlift assembly 27 includes a shaft 32 that is supported for rotationalmovement by the rear mounting members 34 and 35 secured to the left andright frame members 12 a, 12 b, respectively. As shown in FIG. 2, acentral portion of the shaft 32 is covered by a shroud 37. Each end ofthe shaft 32 is connected to the apex of a curved arm 38, havingangularly displaced first and second portions 38 a and 38 b. Curved arms38 are spaced from the mounting members 34, 35 by spacers 36.

The first portions 38 a of curved arms 38 are connected to chains 40that are in turn secured to brackets 42 mounted to the top of the deck24. As viewed in FIG. 2, counterclockwise rotation of shaft 32 resultsin an elevation of first portions 38 a and a raising of the rear portionof deck 24.

The front lift assembly 25 comprises a left lift mechanism 25 a and aright lift mechanism 25 b, which cooperate with the rear lift assembly27 to provide a coordinated lifting of deck 24. The left and right liftmechanisms 25 a, 25 b each comprise a curved arm 44 carried by an axle46 rotationally mounted to front mounting members 48 and 50 that aresecured to frame members 12 a, 12 b. Curved arms 44 are spaced fromfront mounting members 48, 50 by spacers 52 so that the curved arms 72of the front lift assembly 25 are longitudinally aligned with the curvedarms of the rear lift assembly 27. Like curved arms 38 of the rear liftassembly 27, curved arms 44 have angularly displaced first and secondportions 44 a and 44 b. The first portions 44 a are secured to chains 54that connect to mounting brackets 56 attached to the front of deck 24.As viewed in FIG. 2, a clockwise rotation of axles 46 results in anelevation of the first portion 44 a of each curved arm 44 and aconsequent lifting of the front of deck 24. The lifting action of thefront and rear lifting assemblies 25, 27 is coordinated by linking rods58, which are pivotally connected between the second portions 38 b ofcurved arms 38 and the second portions 44 b of curved arms 44.

FIG. 3 is a cross-sectional view of mower 10 taken along line 3—3 ofFIG. 1. As shown in FIG. 3, lift mechanism 26 is connected to a deckheight adjustment apparatus 29, which includes foot pedal assembly 60,lever 66, linking member 70, and deck height adjustment cam 78. Liftmechanism 26 is actuated by foot pedal assembly 60, which includes apivotal connection 62 to a portion of frame 12. Foot pedal assembly 60comprises foot pedal 28, which is secured to curved arm 64 having arearward extending portion 64 a and a forward extending portion 64 b,with the pivotal connection 62 formed at the apex of curved arm 64.Pivotal connection 64 also secures one end of lever 66 relative tocurved arm 64. The forward extending portion 64 b is provided with a peg68 which bears against lever 66 when pedal 28 is depressed to move lever66 in a rearward direction. The opposite end of lever 66 is connected tolinking member 70 that in turn is connected to a rotation plate 72connected to shaft 32.

FIG. 3 illustrates the lifting mechanism 26 and the deck heightadjustment apparatus 29′ where deck 24 is resting at a low heightsetting. Deck 24 is raised initially by depressing foot pedal 28, asillustrated by arrow A, which rotates curved arm 64 counterclockwise.Peg 68 on the forward extending portion 64 b of curved arm 64 engageslever 66 and urges lever 66 toward the rear of mower 10, as illustratedby arrow B. This correspondingly pulls linking member 70 toward the rearof mower 10, as illustrated by arrow C, which pivots rotation plate 72and shaft 32 in a clockwise direction, as illustrated by arrow D. Theclockwise rotation of shaft 32 causes curved arms 38 to pivot in aclockwise direction, as illustrated by arrows E and F. The clockwisepivoting of curved arms 38 lifts first portions 38 a, whichcorrespondingly lift chains 40 and the rear portion of deck 24, asillustrated by arrow G. The clockwise pivoting of rear deck arms 38 alsopull second portions 38 b downward, which pulls linking rods 58 towardthe rear of mower 10, as illustrated by arrow H.

The rearward movement of linking rods 58 pivot curved arms 44counterclockwise, as illustrated by arrows I and J, resulting in adownward movement of second portions 44 b, as illustrated by arrow I.The counter-clockwise pivoting of curved arms 44 lift first portions 44a of curved arms 44, which correspondingly lift: chains 54 and the frontportion of deck 24, as illustrated by arrow K.

As deck 24 is raised and lowered, deck 24 is maintained in longitudinalalignment with mower 10 by a pair of guide arms 74 on each side of deck24. Guide arms 74 have first ends pivotally connected to rear mountingmembers 34 and 35, and second ends pivotally secured to deck 24 bymounting brackets 76. Guide arms 74 provide additional connectionsbetween frame 12 a, 12 b, and deck 24 to inhibit horizontal swingingmotion, and allow deck 24 to be raised in alignment with thelongitudinal axis of mower 10. As deck 24 is raised, guide arms 74 arealso raised at the end connected to mounting brackets 76, as illustratedby arrow L.

Lifting mechanism 26 allows the operator to raise and lower deck 24 withlittle time and effort. Deck 24 is easily and conveniently raised andlowered by actuating foot pedal 28. The operator merely depresses footpedal 28 to lift deck 24 to full height, and releases foot pedal 28 toallow deck 24 to lower down to the desired height. As will be described,the height of deck 28 may be varied by deck height adjustment cam 78that is actuated by the deck height setting control 30 carried by handle22 of mower 10. The deck height adjustment can be performed while mower10 is still running and does not require the operator to stop mower 10and adjust each corner of deck 24 to a new height.

FIG. 4 is an enlarged view of the foot pedal assembly 60 of FIG. 3 withdeck height setting cam 78, which is a rotational cam mechanism utilizedfor setting and maintaining a desired height of deck 24. As shown inFIGS. 4 and 5, deck height setting cam 78, which is comprised of a camwheel 80 secured between opposing plates 82, 84 is provided with aneccentrically positioned axle 86 that is rotatably connected to frame12. Cam wheel 80 has an outer edge surface 88 of a varying radiusrelative to axle 86 of the deck height setting cam 78, where axle 86defines an axis of rotation of cam wheel 80. The outer edge surface 88of cam wheel 80 is aligned for engagement with a protrusion 90 of lever66 so that the range of forward movement of lever 66 is a function ofthe outer edge portion of cam wheel 80 oriented toward protrusion 90.

Deck height setting cam 78 is rotated by deck height control 30 onhandle 22 (shown in FIG. 1). Any suitable mechanical actuator positionedrelative to the handle 22, such as a pneumatic cylinder, a gas-filledcylinder, a ball screw, a chain drive, a rack, a worm gear, or anelectric motor, may be used to rotate the cam wheel 80. In oneembodiment, shown in FIGS. 4 and 5, deck height setting cam 78 includesa plurality of radially spaced pins 92 extending between the opposingplates 82, 84 generally adjacent to an edge portion of cam wheel 80having the greatest radius. A deck height setting cable 94 controlled bydeck height setting control 30 is connected to end pin 92 a such that asdeck height setting cable 94 extends (i.e., lengthens) relative to frame12, cam wheel 80 rotates clockwise, and when the deck height settingcable 94 retracts (i.e., shortens) relative to frame 12, the cam wheel80 rotates counterclockwise. A spring 96 connected by a cable 98 to pin92 b assists the deck height setting cam 78 in rotating clockwise whendeck height setting cable 94 is extended. As shown if FIGS. 4 and 5, theplurality of radially spaced pins 92 define a curved shoulder. In analternative embodiment, the curved shoulder may be a unitary wallstructure extending between the opposing plates 82, 84.

The length of the deck height setting cable 94 is determined by theselected settings of deck height setting control 30 on handle 22. Asillustrated in FIG. 5 a, which is an enlarged view of handle 22, deckheight setting control 30 extends through a slot 100 in panel 102containing deck height setting notches for holding deck height settingcontrol 30 at various positions along slot 100. The notches may belabeled to designate the incremental heights of deck 24. When deckheight setting control 30 is shifted forward along the slot 100 towardthe front of mower 10, as shown in FIG. 5A, deck height setting cable 94extends from frame 12, allowing cam wheel 80 to rotate clockwise.Similarly, when deck height control 40 is shifted along the slot 100toward the rear of mower 10, deck height setting cable 94 retracts toframe 12, allowing cam wheel 80 to rotate counterclockwise.

As shown in FIG. 4, with pedal 28 fully depressed, lever 66 is urgedrearward and, as previously described, deck 24 is elevated. As shown inFIG. 6, when pedal 28 is released, a return spring 104 connected betweenpedal 28 and frame 12 urges pedal 28 to a raised position, asillustrated by arrow M. Foot pedal 28 returns to a position that isgenerally out of the way during normal use, but is ready to be depressedwhen needed. This accordingly allows lever 66 to travel forward in thedirection of arrow N (and deck 24 lowers) until the protrusion 90engages an edge portion of cam wheel 80. The height of deck 24 isthereby maintained according to the relative position of the deck heightsetting cam 78. As the radius of the outer edge 88 of cam wheel 80oriented toward protrusion 90 increases by clockwise rotation of thedeck height setting cam 78, the height at which deck 24 will bemaintained increases. The deck height of mower 10 is thereby easily andquickly enabled by the deck height adjustment mechanism of the presentinvention.

FIG. 7 is a rear view of mower 10, with the lower rear portion of mower10 exposed to illustrate transmission system 160. Transmission system160 is supported in the rear portion of frame 12 of mower 10, is poweredby engine 14, and comprises two hydrostatic transmission systems,generally referred to as 160 a, 160 b, for independently driving leftrear wheel 18 and right rear wheel 20.

FIG. 7 further illustrates the cable connections extending from handle22 to foot pedal assembly 60 and transmission system 160. Deck heightsetting cable 94 is connected to deck height setting control 30 andextends down to connect with foot pedal assembly 60, which is locatedadjacently to transmission system 160. Transmission setting cable 162 isconnected to transmission setting control 168 and transmission system160 for allowing transmission setting control 168 to set the standardoperating speed of mower 10. Left and right transmission engagementcables 164 and 166 are connected to left and right engagement levers 170and 171, respectively, and extend down to left and right transmissionsystems 160 a and 160 b, respectively.

FIG. 8 is an enlarged rear view of mower 10 showing an improvedtransmission system 160 of the present invention, which allows theoperator to easily vary the rate at which wheels 18 and 20 are rotatedfrom a first selected rate to a second higher rate. As shown in FIG. 8,transmission system 160 comprises a left transmission system 160 a and aright system 160 b mounted to frame 12 in a conventional manner. Theleft and right transmission systems 160 a and 160 b are identical, eachcomprising a housing 173 for a transmission 172 that is coupled to anaxle 175 for the respective left and right rear wheels 18 and 20 ofmower 10. In one embodiment, transmission systems 160 a, 160 b arehydrostatic transmission systems made and sold by Hydro-Gear® as modelnumber 310-2400 IZT. Transmission systems 160 a, 160 b are driven by afluid pump driven by engine 14 of mower 10 in a manner known in the art.The rate of speed of the hydrostatic transmission (and thus the rate atwhich wheels 18 and 20 rotate) is a function of the rate at which fluidis pumped through the transmission.

The fluid pumping rate of transmission 172 is varied by rotation of ashaft 178, which is a transmission speed input extending rearward fromthe housing 173 of transmission 172. Shaft 178 is mounted to a top plate174 that has an arm 179 for attachment to the left transmissionengagement cable 164. As shown in FIG. 8, top plate 174 is in a neutralposition. A clockwise rotation of top plate 174 from the neutralposition results in an increase in the fluid pumping rate in a firstdirection and thus the rate at which wheels 18 and 20 rotate to drivemower 10 in a forward direction. Conversely, a counter-clockwiserotation of top plate 174 from the neutral position causes an increasein the fluid pumping rate in an opposite direction, which drives wheels18 and 20 in reverse direction. Top plate 174 is rotatably connected toa guide plate 176, which includes a guide slot 177 for fingers attachedto top plate 174 at locations 174 a and is secured to transmissionhousing 173 via a fixed bolt 180, extending rearwardly from guide plate176 through a window 182 formed in top plate 174. The fixed bolt 180defines a stop that engages the ends 182 a, 182 b of window 182 andthereby restricts the rotation of top plate 174.

When left transmission engagement cable 164 retracts (i.e. shortens)into the cable housing, the upward motion, as illustrated by arrows Yand Z, rotates top plate 174 and shaft 178 in a clockwise direction, asillustrated by arrows AA and AB. Top plate 174 may rotate until the leftend 182 a of window 182 contacts bolt 180. The rotation of shaft 178increases the pump speed of hydrostatic transmission 172, whichcorrespondingly increases the speed of left rear wheel 18. As such, themore left transmission engagement cable 164 is pulled upward, the fasterhydrostatic transmission 172 drive left rear wheel 18. Conversely, ifleft transmission engagement cable 164 is extended (i.e., lengthened)from the cable housing, top plate 174 will rotate counterclockwise,causing hydrostatic transmission 172 to slow left rear wheel 18 down. Iftransmission engagement cable 164 is fully extended, top plate 174 willrotate counter-clockwise from the neutral position illustrated in FIG.8, causing hydrostatic transmission 172 to drive left rear wheel 18 inreverse.

FIG. 9 is also an enlarged rear view of mower 10 with a portion ofmounting bracket 208 removed to show transmission setting system 161.Transmission setting system 161 allows the operator to select a desiredtransmission speed for operating rear wheels 18 and 20. The transmissionsetting system 161, comprises V-shaped arm 222, with a first portion 222a, a second portion 222 b, and an apex 218 that is pivotally mounted toa mounting bracket 208 secured to frame 12 (shown in FIG. 8). The firstportion 222 a of V-shaped arm 222 connects to the transmission settingcable 162, which rotates the V-shaped arm about pivotal connection point219 of apex 218 by extending or retracting the cable from the cablehousing. The second portion 222 b of V-shaped arm 222 is connected aboutpivotal connection 234 to a master-slave shaft 232 that in turn connectsto the second portion of the V-shaped arm associated with the righttransmission system 160 b. Second portion 222 b of V-shaped arm 222 alsoincludes a peg 224, which extends into a slot 220 of a first portion 214a of arm member 214.

Arm member 214 is also pivotally connected to mounting bracket 208 atpoint 219 and further includes a second portion 214 b with a slit 215,which is connected to spring 228. Second portion 214 b is connectedabout a pivotal connection 216 to slot member 210. Spring 228 ispre-biased and provides a resistance to movement of second portion 214 bof arm member 214 in a counterclockwise direction around point 219. Slotmember 210 includes a horizontally longitudinal slot 212′. A pin 186,connected to top plate 174 extends through slot 212 and is retained by aconnector 188. Slot 212 provides a range of travel for pin 186 as topplate 174 rotates clockwise and counterclockwise, with end 213 of slot212 defining a stop surface for pin 186. Slot member 210 thus serves asa means for setting a desired transmission speed by restricting therotation of top plate 174 and shaft 178 according to the position of end213 of slot 212 relative to pin 186.

For example, slot member 210 can be set so that when top plate 174 isrotated clockwise, pin 186 will contact the end 213 of slot 212 beforebolt 180 contacts window portion 182 a of top plate 174. Pin 186encounters resistance at this point due to the connection of spring 228to arm member 214 and slot plate 210 in a countering direction. Theresistance hinders top plate 174 from being further rotated clockwiseand determines the first selected rate at which hydrostatic transmission172 will be driven. The setting for the first selected transmission rateis controlled by the position of transmission control setting 168, whichactuates the transmission setting cable 162.

When transmission setting cable 162 is extended (i.e., lengthened) fromthe cable housing, the downward motion, as illustrated by arrow AK,pivots V-shaped member 222 in a counter-clockwise direction around point219, as illustrated by arrows AL, AM, and AN. When peg 224 reaches theend of slot 220, arm member 214 is urged to pivot counterclockwisearound point 219, as illustrated by arrows AP and AQ, exceeding thecountering force of spring 228, and pulling slot member 210 to theright, as illustrated by arrow AR. This increases the distance of end213 of slot 212 from pin 186 and thus allows a greater range of rotationby top plate 174 before pin 186 contacts end 213 of slot 212 andencounters resistance from spring 228. The greater range of rotation oftop plate 174 and shaft 178 allows left hydrostatic transmission 172 todrive left rear wheel 18 at a higher first selected transmission rate.As such, the extending and retracting of transmission setting cable 162varies the position of slot member 210 and hence the first selected rateof transmission 172 for left rear wheel 18. The right transmission 172operates in the same manner.

FIG. 10 is enlarged rear view of mower 10, focusing on the componentinteractions for exceeding the first selected rate of transmission 172to achieve a second higher transmission speed. As illustrated in FIG.10, top plate 174 is rotated such that pin 186 is contacting the end 213of slot 212. This corresponds to left rear wheel 18 operating at thefirst selected rate designated by transmission setting cable 162, asdescribed in FIG. 9. At this position, top plate 174 encountersresistance from spring 228, hindering further clockwise rotation of topplate 174 and shaft 178.

To obtain a second higher transmission speed, left transmissionengagement cable 164 is further retracted into the cable housing, asillustrated by arrow BA by applying a force to cable 164 that exceedsthe biasing force of spring 228. This causes top plate 174 and shaft 178to rotate further clockwise, as illustrated by arrows BC and BD, andurge pin 186 further to the right, as illustrated by arrow BE. Pin 186drives slot plate 210 to the right, as illustrated by arrow BF, pivotingthe second portion 214 b of arm member 214 counterclockwise, asillustrated by arrow BG, against the biasing force of spring 228. Byexceeding the biasing force of spring 228, top plate 174 and shaft 178are able to fully rotate until bolt 180 contacts the left portion 182 aof slot 182, allowing left hydrostatic transmission 172 to pump at amaximum rate.

This system allows the operator to drive left rear wheel 18 at fullspeed without having to stop mower 10 and adjust transmission settingcable 162. To return to the first selected rate, the left transmissionengagement cable 164 is lengthened until pin 186 no longer urges slotplate 210 to the right. The interactions described above apply in thesame manner to the components of hydrostatic transmission system 160 b.As such, transmission system 160 allows the operator to override thefirst selected rate of rear wheels 18 and 20, individually orsimultaneously, to reach the second higher rate.

While the present invention has been described relative to independenthydrostatic transmission systems, it is to be understood that the leveractuated drive control system described can be utilized with anytransmission that includes or can be adapted to operate by a rotarytransmission speed input, i.e., like shaft 178.

FIG. 10A is an enlarged view of mower 10, illustrating an alternativeembodiment for use with top plate 174. After exiting top plate 174,shaft 178 further extends rearward through first member 300 and secondmember 302, allowing both first and second members 300, 302 to rotatewith top plate 174. First member 300 includes a first portion 300 a anda second portion 300 b that is formed at an angle relative to the firstportion 300 a. Second member 302 includes a first portion 302 a and asecond portion 302 b that is formed at an angle relative to the firstportion 302 a. The first portion 300 a of first member 300 is spacedfrom the first portion 302 a of second member 302 with the ends of thefirst portion 300 a and first portion 302 a interconnected by a spring304. The second portion 300 b of first member 300 and the second portion302 b of second member 302 are spaced apart and are generally parallelto one another. Extending between second members 300 b and 302 b is ashoulder 308 that is fixed to and extends rearward from guide plate 176.

Shoulder 308 bears against second portion 300 b of first member 300 toprevent it from rotating clockwise. Shoulder 308 also bears against thesecond portion 302 b of second member 302 to prevent it from rotatingcounterclockwise. Also extending rearwardly from top plate 174 is an arm306 adjacent to shoulder 308. When top plate 174 rotates clockwise, arm306 engages the second portion 302 b of second member 302 to rotate itclockwise with top plate 174. Similarly, when top plate 174 rotatescounterclockwise, arm 306 engages the second portion 300 b of firstmember 300 to rotate it counterclockwise with top plate 174.

As previously mentioned, second portions 300 b and 302 b areinterconnected by spring 304 for assisting top plate 174 to return tothe neutral position, as illustrated in FIG. 10A.

FIG. 11 is an enlarged view of handle 22 illustrating the controlsrelating to transmission system 160. Transmission setting control 168extends through a slot 169 in panel 102 for designating the firstselected rate for rotating rear wheels 18 and 20. When transmissionsetting control 168 is shifted toward the front of mower 10,transmission setting cable 162 is lengthened, as described above in FIG.9. Similarly, when transmission setting control 168 is shifted towardthe rear of mower 10, transmission setting cable 162 is retracted fromthe cable housing.

In one embodiment, left and right transmission engagement levers 170,171 are pivotally mounted to handle 22 and independently governhydrostatic transmission systems 160 a and 160 b, respectively. Whenleft transmission engagement lever 170 is moved toward cross bar 110 orpulled toward the rear of mower 10, left transmission engagement cable164 is retracted and lengthened, respectively. Right transmissionengagement lever 171 interacts with right transmission engagement cable166 in the same manner.

Levers 260 and 262 extend alongside left and right transmissionengagement levers 170, 171, respectively. Levers 260 and 262 provideoperator presence controls for mower 10, as required by governmentalregulations to protect operators. While at least one of levers 260 and262 are squeezed against their corresponding engagement lever 170, 171,mower 10 may be operated. If both levers 260, 262 are released, thenengine 14 of mower 10 is shut off, as is standard with motorized lawnmowers. When left and right transmission engagement levers 170, 171 restin neutral positions, as shown in FIG. 1, top plates 174 of transmissionsystem 160 is also in the neutral position previously shown in FIG. 8.Rear wheels 18 and 20 are engaged for forward rotation when left andright transmission engagement levers 170, 171 are moved toward cross bar110. Generally, the further forward left and right transmissionengagement levers 170, 171 are moved relative to crossbar 110, thefaster rear wheels 18 and 20 are driven. Mower 10 travels at the firstselected rate when left and right transmission engagement levers 170,171 encounter the resistance from springs 228 of transmission settingsystem 161. Springs 228 hinder further forward movement of left andright transmission engagement levers 170, 171 toward cross bar 110.

The extent to which left and right transmission engagement levers 170,171 are able to move toward cross bar 110 before encountering resistanceis based upon the setting of transmission setting control 168. If, forexample, transmission setting control 168 is fully shifted back towardthe rear of mower 10, transmission setting cable 162 is frillyretracted, setting the first selected rate to the lowest speed in amanner described above. Left and right transmission engagement levers170, 171 will encounter the resistance after being moved a shortdistance toward cross bar 110. At the point where left and righttransmission engagement levers 170, 171 encounter resistance,hydrostatic transmission systems 160 a and 160 b drive rear wheels 18and 20 forward, respectively, at a first selected rate.

If transmission setting control 168 is pivoted forward toward the frontof mower 10, such that transmission setting control 168 is positioned atthe mid-point between fully forward and fully rearward, transmissionsetting cable 162 will be lengthened to a midway point. This will setthe first selected rate at a speed midway between full speed and thelowest speed in a manner described above. Left and right transmissionengagement levers 170, 171 are capable of moving further toward crossbar 110, before encountering the resistance. As such, when left andright transmission engagement levers 170, 171 encounter the point ofresistance, they hydrostatic transmission systems 160 a and 160 b driverear wheels 18 and 20 forward, respectively, at a mid-speed.

Finally, if transmission setting control 168 is fully shifted toward thefront of mower 10, transmission setting cable 162 will be fullylengthened, setting the first selected rate at full speed in a mannerdescribed above. Left and right transmission engagement levers 170, 171are capable of being moved fully forward toward cross bar 110 withoutencountering the resistance. At the fully forward position, hydrostatictransmission systems 160 a and 160 b drive rear wheels 18 and 20forward, respectively, at a first selected rate that is full speed.

With known mowers, adjustments to the transmission speed require anoperator to stop the forward progression of the mower by bringing thetransmission engagement levers to their neutral positions, beforeshifting the transmission setting control to a different rate. Onlyafter resetting the transmission setting control can the operator thenre-engage the transmissions to continue forward at the new rate. Thiscan be time consuming and tedious, especially when a higher rate ofspeed is only temporarily needed to reverse the mowing direction or tomove the mower to more distant areas requiring mowing. Mower 10overcomes this limitation by being able to operate at a second higherrate without adjusting transmission setting control 168. This occurswhen left and right transmission engagement levers 170, 171 are furtherpressed to surpass the encountered resistance. This correspondinglyallows left and right transmission engagement cables 164, 166 to rotatetop plates 174 further to exceed the biasing force of springs 228 intransmission system 160, respectively. This overrides transmissionsetting control 168 allowing mower 10 to achieve full speed, merely byadjusting the position of left and right transmission engagement levers170, 171.

Mower 10 may also operate in reverse at a constant speed, as discussedabove. This is accomplished by pulling left and right transmissionengagement levers 170, 171 back from their neutral position, toward therear portion of handle 22.

Mower 10 additionally allows an independent operation of left rear wheel18 and right rear wheel 20. Through the use of independent hydrostatictransmissions, left rear wheel 18 may be operated at a speed differingfrom right rear wheel 20. The operator may independently operate leftrear wheel 18 at a desired speed, regardless of how right rear wheel 20is operated, such as during turning maneuvers.

Rapid turns of mower 10 may be accomplished by a full forward movementof left transmission engagement lever 170 and a full rearward movementof right transmission engagement lever 171. This arrangement allows leftrear wheel 18 to operate, at full speed, while right rear wheel 20operates in reverse, allowing mower 10 to take a sharp and rapid turnaround an axial point of right wheel 20.

As described above, mower 10 is a walk-behind lawn mower that providesboth a rapid and efficient system for adjusting the height of deck 24and an advantageous drive system. The deck height adjustment systemallows the operator to adjust the height of deck 24 without shuttingdown engine 14, and without having to manually adjust individual cornersof deck 24, which is tedious and time consuming. The drive system allowsmower 10 to be operated at the first selected rate, while also allowingmower 10 to override the first selected rate. The override allows mower10 to reach the second higher rate without an adjustment of transmissionsetting control 168. This, in addition to individually driven wheels,reduces the time required to mow intended areas.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention. In particular, it is to be understood thatthe lever actuated drive control system of the present invention may beimplemented in riding mowers which employ independent steering levers,in which case each steering lever serves to actuate the respectivetransmission system comparable to the operation described relative tolevers 170, 171.

1. A walk behind mower having an operator handle and a pair of drivewheels operably connected to an engine-driven transmission, the walkbehind mower comprising: a lever operably connected to the handle andmoveable between a starting position and a second position; atransmission speed input operably connected to the lever, thetransmission having a rate of speed that is a function of a rotationalposition of the transmission speed input, wherein the transmission is inneutral when the lever is in the starting position and wherein thetransmission is at a highest rate of speed when the lever is in thesecond position; a first member connected to the transmission speedinput and rotatable therewith; and a second member having a stop surfacepositioned relative to the first member and operably engageable with thefirst member, the stop surface of the second member having a homeposition near the first member and being moveable away from the homeposition, the second member being biased toward the home position;wherein a first amount of force applied to the lever moves the leveraway from the starting position and causes the first member to rotateand engage the stop surface before the lever reaches the secondposition, and wherein the lever is moveable to the second position byapplying a second amount of force to the lever to cause the first memberto further rotate and move the second member away from the homeposition.
 2. The walk behind mower of claim 1 wherein the first membercomprises a plate, the plate being coaxially mounted to the transmissionspeed input, the plate having a first radial portion operably connectedto the lever and a second radial portion radially spaced from the firstradial portion, the second radial portion configured to engage the stopsurface of the second member.
 3. The walk behind mower of claim 2wherein the lever is operably connected to the plate by a cable.
 4. Thewalk behind mower of claim 2 wherein the second member is configuredwith a slot, wherein an end of the slot defines the stop surface of thesecond member, and wherein the second radial portion of the plate ispositioned within the slot.
 5. The walk behind mower of claim 4 whereinthe second member comprises a first portion and a second portionpivotally connected to an end of the first portion and extending at anangle relative to the first portion, wherein the first portion isconfigured with the slot and the second portion is pivotally connectedto a frame member of the mower.
 6. The walk behind mower of claim 5 andfurther comprising a spring connected between the frame member and thesecond portion of the second member, the spring biasing the end of theslot of the second member toward the home position.
 7. The walk behindmower of claim 1 wherein the home position of the stop surface of thesecond member is adjustable.
 8. The walk behind mower of claim 7 andfurther comprising a control operably connected to the handle andfurther operably connected to the second member, wherein the homeposition of the stop surface of the second member is a function of asetting of the control.
 9. The walk behind mower of claim 8 and furthercomprising a third member having a first radially extending portion anda second radially extending portion, the second radially extendingportion extending at an angle relative to the first radially extendingportion, the third member pivotally connected to a frame member of themower, wherein the first radially extending portion is operablyconnected to the control and wherein the second radially extendingportion is operably engageable with the second member.
 10. A method ofoperating a transmission of a motorized walk behind mower between afirst selected transmission speed less than a maximum transmission speedand the maximum transmission speed, the method comprising: operablyconnecting a lever on a handle of the mower to a transmission speedinput, the transmission speed input being moveable between a neutralposition and a second position corresponding to the maximum transmissionspeed; operably connecting the transmission speed input to a moveablemember having a stop surface; and biasing the moveable member in a firstposition with the stop surface proximate the transmission speed input;wherein the transmission speed input encounters the stop surface todefine the first selected transmission speed when a first amount offorce is applied to the lever; and wherein the transmission speed inputmoves the moveable member and reaches the second position when a secondamount of force is applied to the lever.
 11. The method of claim 10 andfurther comprising adjusting the first position of the moveable memberto change a distance of the stop surface relative to a neutral positionof the transmission speed input.
 12. The method of claim 11 wherein thestep of adjusting the first position of the moveable member comprisesincreasing the distance of the stop surface relative to the neutralposition of the transmission speed input.
 13. A walk behind mower havingan operator handle and a pair of drive wheels, each drive wheel beingoperably connected to a first and second independent engine-driventransmission, the walk behind mower comprising: a pair of leversoperably connected to the handle, each lever being moveable between astarting position and a second position; a transmission speed inputassociated with each of the first and second transmissions and operablyconnected to each of the pair of levers, the first and the secondtransmission each having a rate of speed that is a function of arotational position of the transmission speed input, wherein each of thefirst and the second transmission is in neutral when a respective leveris in the starting position and wherein each of the first and the secondtransmission is at a highest rate of speed when the respective lever isin the second position; a first member connected to each transmissionspeed input of the first and second transmissions and rotatabletherewith; and a second member associated with each of the first andsecond transmissions and having a stop surface positioned relative toeach first member and operably engageable with the respective firstmember, the stop surface of the second member having a home positionnear the respective first member and being moveable away from the homeposition, the second member being biased toward the home position;wherein a first amount of force applied to the pair of levers moves thelevers away from the starting position and causes the respective firstmembers to rotate and engage the stop surface before the levers reachthe second position, and wherein the levers are moveable to the secondposition by applying a second amount of force to the levers to cause therespective first members to further rotate and move the second memberaway from the home position.
 14. The walk behind mower of claim 13wherein the first member comprises a plate, each respective plate beingcoaxially mounted to the respective transmission speed input, each platehaving a first radial portion operably connected to a respective one ofthe pair of levers and a second radial portion radially spaced from thefirst radial portion, the second radial portion configured to engage thestop surface of the second member.
 15. The walk behind mower of claim 14wherein each lever of the pair of levers is operably connected to therespective plate by a cable.
 16. The walk behind mower of claim 15wherein the home position of the stop surface of the second member isadjustable.
 17. The walk behind mower of claim 16 and further comprisinga control operably connected to the handle and further operablyconnected to at least one of the second members, wherein the homeposition of the stop surface of each second member is a function of asetting of the control.
 18. The walk behind mower of claim 17 whereineach second member is configured with a slot, wherein an end of the slotdefines the stop surface of the second member, and wherein the secondradial portion of each plate is positioned within the respective slot.19. The walk behind mower of claim 18 wherein each second membercomprises a first portion and a second portion pivotally connected to anend of the first portion and extending at an angle relative to the firstportion, wherein the first portion of each second member is configuredwith the respective slot and each second portion is pivotally connectedto a frame member of the mower.
 20. The walk behind mower of claim 19and further comprising a linking member connected between the secondportion of each second member.
 21. The walk behind mower of claim 20 andfurther comprising a third member associated with each second member,each third member having a first radially extending portion and a secondradially extending portion, the second radially extending portionextending at an angle relative to the first radially extending portion,each third member pivotally connected to a frame member of the mower,wherein the second radially extending portion of each third member isoperably engageable with the respective second member and wherein thefirst radially extending portion of a first one of the third members isoperably connected to the control.
 22. The walk behind mower of claim 19and further comprising a spring connected between the frame member andeach second portion of the respective second member, each spring biasingthe end of the respective slot of the second member toward the homeposition.